Method and system for metadata extraction from master-slave cameras tracking system

ABSTRACT

An embodiment of the present invention includes a master camera that may record master metadata regarding an object of interest and communicate the master metadata to a slave camera. The slave camera may zoom, pan, or tilt to isolate and record more detailed image data regarding the object of interest based on the master metadata. In addition, the slave camera may record slave metadata regarding the object of interest. The master and slave metadata may be stored associated with the recorded image data enabling a later search for the object of interest to be expedited. The recorded image data including the object of interest may be identified with greater ease as it may be guided by the master or slave metadata, or a combination thereof. According to embodiments presented herein, processing time for searching and identifying an object of interest may be reduced by enabling a search on the metadata associated with image data, rather than by searching the image data itself.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/682,606, filed Nov. 20, 2012. The entire teachings of the aboveapplication are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Video surveillance systems are used at many locations such as at a bank,store, airport, or any other location where security may be of interest.A video surveillance system may include a video camera that provides avideo stream capturing images of whatever is within the field-of-view ofthe video camera's lens. The video stream may be monitored by a humanoperator and recorded for later review.

SUMMARY OF THE INVENTION

A method, corresponding system and apparatus, employed in conjunctionwith video surveillance are disclosed herein. An example embodimentincludes a method of enabling retrieval of information from a videosurveillance system that may comprise automatically identifying anobject of interest in a video scene of a master camera or a slavecamera, where the object of interest for the slave camera may bedetermined as a function of metadata from the master camera. The exampleembodiment may include automatically classifying at least one feature inthe object of interest. The example embodiment may also include storinga representation of the at least one feature in a form of metadata,including the metadata from the master camera to the slave camera,associated with video of at least the slave camera in a manner enablingretrieval of information about the object of interest. The object ofinterest may be a real-world object.

The metadata may further include slave metadata associated with theobject identified. Retrieval may be more efficient on average via themetadata than via direct observation of the video. Identifying an objectof interest may include applying background subtraction to removebackground objects from the video scene.

The metadata may further include slave metadata associated with theobject identified, and the example embodiment may further includetracking the object of interest by adjusting the slave camera's field ofview based on object information included in the metadata from themaster camera. Adjusting the slave camera's field of view may includezooming in on the object of interest and following movement of theobject of interest. The slave metadata may include a start time stampindicating a start time of the slave camera's tracking the object and anend time stamp indicating an end time of the slave camera's tracking theobject. Adjusting the slave camera's field of view may be further basedon processing the video scene at the slave camera based on the objectinformation from the master camera. The slave metadata may includedetailed object information extracted from the video scene by the slavecamera. Processing the video scene may include searching of one or moreimage frames of the slave camera captured during tracking, the searchingmay be based on the object information included in the metadata from themaster camera and the slave camera. Adjusting the slave camera's fieldof view may include directing the slave camera to a pan and tiltposition. The example embodiment may further include analyzing one ormore image frames of the slave camera during tracking, extractingdetailed object information from the one or more image frames, andstoring the detailed object information extracted as the slave metadata.

Automatically classifying at least one feature in the object of interestmay include categorizing the object of interest as a person, vehicle, oranimal.

Automatically classifying at least one feature in the object of interestmay include classifying movement of the object identified as stationaryor moving, wherein a moving classification may further include anestimated rate of movement of the object identified.

The metadata may include a time stamp, identified color, identifiedlicense plate number, aspect ratio, or bounding box for the object ofinterest.

The form of metadata may further include slave metadata associated withthe object identified. The example embodiment may further includestoring the metadata on a server.

Automatically identifying the object of interest, automaticallyclassifying at least one feature in the object of interest, and storingthe representation of the at least one feature in the form of metadatamay occur during recording of the video scene.

Automatically identifying the object of interest, automaticallyclassifying at least one feature in the object of interest, and storingthe representation of the at least one feature in the form of metadatamay occur after recording of the video scene.

The form of metadata further includes slave metadata associated with theobject identified. The example embodiment may further include presentingthe form of metadata and classifications of the object identified to auser.

Another example embodiment includes a system for enabling retrieval ofinformation from a video surveillance system. The example embodiment mayinclude a master camera, a slave camera, and a server communicativelycoupled. The master camera may be configured to identify an object ofinterest automatically in a video scene of the master camera and tocommunicate master classification information of the object identifiedin the form of master metadata to the slave and to the server. The slavecamera may be configured to determine more detailed slave classificationinformation based on the master classification information communicatedand to communicate the more detailed slave classification information inthe form of slave metadata to the server. The server may be configuredto store the master classification information and the detailed slaveclassification information in a manner enabling retrieval of informationabout the object of interest.

The slave camera may be further configured to communicate the moredetailed slave classification information in the form of slave metadatato the master camera or an indication that the master classificationinformation communicated is incorrect and the server may overwrite anobject category of the metadata from the master camera with an objectcategory of the metadata from the slave camera.

The master camera may be further configured to include a master boundingbox for the video scene in the form of metadata and the slave camera isfurther configured to define a slave bounding box for the video scenebased on the master bounding box, the more detailed slave classificationinformation may be based on data of the video scene within the slavebounding box. The slave camera may define the slave bounding box as afunction of metadata from the master and its own processor. The mastermetadata may include data of a master bounding box and the slave cameramay use data of objects within the master bounding box.

Another example embodiment of a method includes enabling retrieval ofinformation from a video surveillance system. The example embodiment mayinclude presenting a representation of at least one feature in an objectof interest in a form of metadata from a master camera and a slavecamera in a manner enabling retrieval of information about the object ofinterest. The metadata from the master camera may include classificationinformation about the object of interest. The metadata from the slavecamera may include more detailed classification information about theobject of interest.

Further, an example embodiment of a non-transient computer-readablemedium having stored thereon a sequence of instructions, which, whenloaded and executed by a processor may cause the processor to retrieveinformation from a video surveillance system. The sequence ofinstructions may further cause the processor to automatically identifyan object of interest in a video scene of a master camera or a slavecamera, where the object of interest for the slave camera may bedetermined as a function of metadata from the master camera. Thesequence of instructions may further cause the processor toautomatically classifying at least one feature in the object ofinterest. The sequence of instructions may further cause the processorto store a representation of the at least one feature in a form ofmetadata, including the metadata from the master camera to the slavecamera, associated with video of at least the slave camera in a mannerenabling retrieval of information about the object of interest.

It should be understood that embodiments of the present invention can beimplemented in the form of a method, apparatus, system, or computerreadable medium with program codes embodied thereon. In general, itshould be understood that elements of the method, block, and flowdiagrams described herein may be implemented in software, hardware,firmware, as understood by one of ordinary skill in the art. Exampleembodiments of the present invention may include a non-transitorycomputer readable medium containing instructions that may be loaded andexecuted by a processor, and, when executed, cause the processor tocomplete methods described herein. For ease of reading, the term“system” is used in various portions of the description and mayrepresent some or all forms of embodiments and implementations of thepresent invention, such as systems, methods, apparatuses, devices,computer readable media, network nodes, and networks.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1A illustrates a system for enabling retrieval of information froma video surveillance system.

FIG. 1B illustrates an embodiment of metadata.

FIG. 2 illustrates a flow diagram of an embodiment of a method ofenabling retrieval of information from a video surveillance system.

FIG. 3A and FIG. 3B illustrate a flow diagram of another embodiment of amethod of enabling retrieval of information from a video surveillancesystem.

FIG. 4 illustrates a flow diagram of yet another embodiment of a methodof enabling retrieval of information from a video surveillance system.

FIG. 5 is a block diagram of an example internal structure of a computerin which various embodiments of the present invention may beimplemented.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

Operators may need to view recorded surveillance image data in order toidentify an object of interest that may be included in the recordedsurveillance image data. The search for the object of interest may be alaborious and time consuming task for an operator. According toembodiments disclosed herein, a slave camera may be configured to zoomin on an object of interest in order to provide more detailed images.Whenever an object is detected, the slave camera may be directed to viewthe details of the scene. Important information may be extractedautomatically enabling a more useful video surveillance system.

According to one embodiment, a master camera may record master metadataregarding an object of interest and communicate the master metadata to aslave camera. The slave camera may zoom, pan, or tilt to isolate andrecord more detailed image data regarding the object of interest basedon the master metadata. In addition, the slave camera may record slavemetadata regarding the object of interest. The master and slave metadatamay be stored associated with the recorded image data enabling a laterexpedited search for the object of interest. The recorded image dataincluding the object of interest may be identified with greater ease asit may be guided by the master or slave metadata, or a combinationthereof.

FIG. 1A illustrates a system for enabling retrieval of information froma video surveillance system 100. The system 100 may comprise a mastercamera 102, a slave camera 104, a user device 128, and a server 106communicatively coupled via a computer network 108. The computer network108 may be wired, wireless, or any combination thereof.

According to embodiments disclosed herein, metadata from a master camera102 may be communicated to one or more slave cameras 104, providinginformation to the one or more slave cameras to enhance processingperformance and capabilities of the one or more slaves. For example, themaster camera 102 may communicate color or aspect ratio to be used by aslave to identify important objects. By providing a slave camera withmetadata 150 that may include attributes such as location, size, movingspeed, moving direction, shape, color or aspect ratio, the slave cameramay use the information to reduce processing for finding the importantobjects (e.g., the one or more objects of interest). Processing time forsearching and identifying an object of interest may be reduced byenabling a search on the metadata associated with image data, ratherthan by searching the image data itself. Objects in the field of view ofa master camera may be classified by a scene analyzer. The sceneanalyzer may be a method for analyzing input video and generatingclassification information in the form of metadata for one or moreobjects of interest included in the input video. Object classificationmay be performed by the master camera or by an external server 106 orany other suitable device or system. The example embodiment may furtherinclude presenting the form of metadata and classifications of theobject identified to a user 118. If presenting, presenting the form ofmetadata of the object identified to a user may include presenting onany suitable display device, such as the user device 128.

The master camera 102 may be configured to identify an object ofinterest automatically in a video scene of the master camera and tocommunicate master classification information of the object identifiedin the form of metadata 112 a to the slave and to the server. The mastercamera 102 may include a processing engine (not shown) configured toperform general background-based scene analysis. After performing theanalysis, useful information, in the form of metadata, may be extracted.An object of interest may be stationary or in motion. The slave cameramay be configured to determine more detailed slave classificationinformation based on the master classification information communicated.The slave camera may further be configured to communicate the moredetailed slave classification information in the form of metadata 112 bto the server.

The server 106 may be configured to store the master classificationinformation and the detailed slave classification information in amanner enabling retrieval of information about the object of interest.The master classification information and the detailed slaveclassification information may be stored in memory (not shown) of theserver 106 or in a database 114 communicatively coupled to the server106. The server 106 may store a representation of at least one featureof the object of interest in a form of metadata 122. The metadata 122may include the master metadata 112 a or the slave metadata 112 b or anycombination thereof. The metadata 122 may be associated with video 126of at least the slave camera in a manner enabling retrieval ofinformation about the object of interest.

The master camera 102 and the slave camera 104 may be megapixel camerasor other suitable devices for capturing video in a surveillance system.The master camera 102 or slave camera 104 may be devices or systems. Forexample, the master camera 102 or slave camera 104 may be a digitalvideo camera coupled to a computer or comprising a processor and memory.The master camera 102 may be fixed type master camera or any othersuitable video capturing device. The slave camera 106 may be a pan,tilt, and zoom (PTZ) camera or any other suitable video capturingdevice. Different kinds of cameras may be used for the master or theslave camera. Any suitable camera known by one or ordinary skill in theart may be used. For example, a perspective, omni, thermal, near-IR,color, black-and-white, telephoto, zoom, or any other suitable camera,or any suitable camera/lens combination may be used.

The master camera 102 and the slave camera 104 may providehigh-definition video streams to the server 106. The master camera 102may configure the slave camera 104 to monitor a wide field of view andthen digitally zoom in on a particular area or object of interest. Forexample, the video scene may include a truck 116 that may be leaving abank. The truck 116 may be driven by a bank robber, and the object ofinterest 110 may be the license plate located on the truck 116. Theslave camera 104 may be configured to digitally zoom in on the licenseplate 110, and, in this embodiment, an image 110′ of the license plate110 may be retrieved more quickly than previously possible throughefficiencies gained through use of the metadata. Another slave camera(not shown) may be configured to track the face of the bank robberdriving the truck via face detection.

The system of FIG. 1A illustrates one master camera 102 that may capturevideo of an entire surveillance area 120. The slave camera 104 mayprovide high-resolution images of one or more objects of interest 110.While FIG. 1A shows only one master and one slave camera, it should beunderstood that there may be multiple masters and/or there may bemultiple slaves. For example, multiple slave cameras may be associatedwith a given master camera.

The master camera 102 and the slave camera 106 may communicate to enablea tracking system. Master and slave cameras may communicate in anysuitable manner. For example, communication may be via the Internetusing wireless or wired connections using any suitable protocol. Themaster and slave cameras may oversee an entire surveillance area. Aslave camera may be directed to any region of interest in the entiresurveillance area. The slave camera may be configured to zoom in on anobject of interest in order to provide more detailed images. Whenever anobject is detected, a slave camera may be directed to view the detailsof the scene. Important information may be extracted automaticallyenabling a more useful video surveillance system.

FIG. 1B illustrates an embodiment of metadata 150. The metadata 150 mayinclude an object identifier 152, unique camera identifier 154, one ormore time stamps 156, a bounding box 158, color 160, velocity 162,object type 164, event type 166, facial features, aspect ratio 160, andother suitable data 170. In terms of the scene 120 illustrated in FIG.1A, a bounding box 158 may define a region of interest 124 in a videoscene 120. The master metadata 112 a or the slave metadata 112 b mayinclude all or any portion of the metadata 150.

The metadata 112 a may be sent to server 106 for storing on a database114. The slave camera 104 may “listen” to the master camera 102. Forexample, the master camera 102 may detect an object and assign one ormore slave cameras to track the object. According to one aspect, themaster camera 102 may send a “move” command to the slave camera 104.Along with the move command, a portion of the metadata 112 a′ of theobject from the master camera 102 may be sent to the slave camera 104,such as the identifier of the master camera 102, the identifier of theobject, the one or more time stamps, the color, the object type, etc.The slave camera 104 may track (e.g., follow) the object based on themetadata from the master camera 102.

According to embodiments disclosed herein, the metadata from the mastercamera 102 may be used to initialize specific processing that enablesthe slave camera 104 to find the object if the slave camera 104 haslimited real-time processing power. After the processing, the slavecamera 104 may extract metadata, of similar type as the metadata of themaster camera 102. For example, the extracted metadata from the slavecamera 102 may include one or more time stamps, bounding box, color,etc. Similar to the master camera 102 metadata 112 a, the slave camerametadata 112 b may be sent to the server 106 for storing on a database114. In addition, all or a portion of the slave camera metadata 112 b′may be sent to the master camera 102. Motion vectors of the slavecameras may be calculated via an optical flow method. The object in thefield of view of the slave camera can be extracted via motion vectorclustering if an object is moving against the background.

FIG. 2 illustrates a flow diagram of an embodiment of a method ofenabling retrieval of information from a video surveillance system(200). The method may start (202) and automatically identify an objectof interest in a video scene of a master camera or a slave camera, theobject of interest for the slave camera being determined as a functionof metadata from the master camera (204). The method may automaticallyclassify at least one feature in the object of interest (206). Themethod may store a representation of the at least one feature in a formof metadata, including the metadata from the master camera to the slavecamera, associated with video of at least the slave camera in a mannerenabling retrieval of information about the object of interest (208).The method thereafter ends (210) in this example embodiment.

According to one embodiment, the server 106 may link the metadata 112 aand 112 b received from master and slave cameras. The link between themetadata of the master camera 102 and the slave camera 104 may serve asa guide for information retrieval. For example, an object or event ofthe master camera 102 may be located, and the link may guide a processoraccessing the database to the record of the slave camera 104 in order toretrieve the corresponding image or video clip from the slave camera104. According to another aspect, the metadata from the slave camera mayinclude the identifier of the master camera, the identifier of theobject on the master, and timestamps that correspond to the beginningand the end of tracking. The slave metadata may be retrieved by usingthe identifier of the master camera and the identifier of the object ofthe master camera. According to yet another embodiment, the mastercamera 102 may add some extra information to the metadata, such as anidentifier of the slave camera that received the move command.

According to another embodiment, the server 106 may search the database114 to find the object. If the object on the master camera 102 is foundthe video clip of the slave during the tracking of the object may beretrieved from the server 106. If the slave camera 104 has real-timeprocessing power, metadata similar to the master metadata may have beensent and recorded, along with the video clip, and the image of the slavecamera satisfying search criteria may be retrieved.

According to embodiments disclosed herein, metadata may be extracted byfirst applying a background subtraction-based method. The method may beused by the master camera to perform basic object detection andclassification. Once the object is found, its color, direction,velocity, location, etc. may be obtained. More detailed information maybe extracted from the original source image. According to one aspect,processing may be constrained by the image size. For example, if thesource image is of high-definition television size, then the size of theprocessed image is likely to be Common Intermediate Format (CIF).According to another aspect, a more detailed image block may beextracted from the original high definition source image to obtain moremetadata, such as color and other texture information.

According to the information obtained from the master camera, the slavecamera may be moved to view more detailed information. Metadata from theslave camera may simply include a time stamp at the start of trackingand a time stamp at the end of tracking. A slave camera may perform aspecific search based on the metadata information of the master camera.For example, object color and object type information. In the example,the master camera metadata may specify that an object type is human anda color is red, then a search may be performed on each image frame ofthe slave camera from when it begins tracking to when it terminatestracking. The search may be first configured to specifically look forhumans. Color may be applied to speed up the search. Different searchmethods may be utilized, each search method targeting a specific objectfeature. The specific object feature may be specified in the metadata.

According to another embodiment, an assumption may be made that theinformation from the master camera is not accurate enough due to thesmall size of the object. In this example, the master camera may firstdirect the slave to the correct pan/tilt position, but with a lesserzooming factor. After the slave camera arrives at the position directed,a frame subtraction method or optical flow method may be used to analyzethe scene and extract more accurate metadata. After extracting the moreaccurate metadata, the slave may return to a listening device statefollowing a command from the master camera.

According to one embodiment, a master camera may extract metadataregarding an object of interest and communicate the metadata to a slavecamera directly or via the server. The slave camera may provide moredetailed information regarding the object of interest as the slavecamera may zoom, pan, or tilt to isolate and capture more detailed imagedata regarding the object of interest. Metadata may be stored associatedwith the recorded image data enabling a later search for the object ofinterest to be expedited and enabling identification of the recordedimage data including the object of interest with greater ease.

FIG. 3A and FIG. 3B illustrate a flow diagram of another embodiment of amethod of enabling retrieval of information from a video surveillancesystem (300). The method may start (302) and decide whether or notcontinue during recording of the video scene (304) or to wait (306) forafter recording (308). The method may continue and automaticallyidentify an object of interest in a video scene of a master camera or aslave camera, the object of interest for the slave camera beingdetermined as a function of metadata from the master camera (310). Themethod may check for whether or not to remove background objects fromthe video scene (312). If yes, identifying an object of interest mayinclude applying background subtraction to remove background objectsfrom the video scene (314) and the method may continue and check whetheror not to track the object of interest by adjusting the slave camera'sfield of view based on object information included in the metadata fromthe master camera (316)

If tracking the object of interest by adjusting the slave camera's fieldof view based on object information included in the metadata from themaster camera (318). The method may enable recording of a start timestamp indicating a start time of the slave camera's tracking the objectand an end time stamp indicating an end time of the slave camera'stracking the object in the slave metadata (326). The method may checkwhether or not to direct the slave camera to a pan position (336). Ifyes, adjusting the slave camera's field of view may include directingthe slave camera to a tilt position (338). The method may further checkwhether or not to direct the slave camera to a tilt position (340). Ifyes, adjusting the slave camera's field of view may include directingthe slave camera to a tilt position (342) and the method may continue.

The method may check whether or not to zoom in on the object of interestand follow movement of the object of interest (320). If yes, the methodmay zoom in on the object of interest and follow movement of the objectof interest (322). The method may further check for whether or not toprocess the video scene (328). If not, the method may continue and checkif processing the video scene is to occur (328). If processing the videoscene is not to occur (328), the method may continue and analyze one ormore image frames of the slave camera during tracking (344).

If processing the video scene is to occur (328), processing the videoscene at the slave camera may be based on the object information fromthe master camera and the slave metadata may include detailed objectinformation extracted from the video scene by the slave camera (330).More sophisticated metadata extraction methods may be applied to theslave camera, because the slave camera may be in a constant state ofmovement. For example, two consecutive frames of the slave camera may bealigned by warping, and frame subtraction on the aligned frames may beused to detect and classify the object.

If processing the video scene, a check may be made for whether or not tosearch stored representations of the video scene (332). If processingincludes searching, a search may be made on one or more image frames ofthe slave camera captured during tracking, the searching may be based onthe object information included in the metadata from the master cameraand the slave camera (334).

The method may analyze one or more image frames of the slave cameraduring tracking (344). The method may further extract detailed objectinformation from the one or more image frames (346) and store thedetailed object information extracted as the slave metadata (348) andthe method may continue on a same path as would be taken if not trackingthe object of interest by adjusting the slave camera's field of view(316). For example, the method may continue to automatically classify atleast one feature in the object of interest (350).

A check may be made for whether or not the object of interest is aperson, vehicle, or animal (352). Automatically classifying at least onefeature in the object of interest may include categorizing the object ofinterest as a person, vehicle, or animal (354). Further, a check may bemade as to whether or not the object of interest is stationary (356). Ifyes, automatically classifying at least one feature in the object ofinterest may include classifying movement of the object identified asstationary (358). If not, automatically classifying at least one featurein the object of interest may include classifying movement of the objectidentified as moving and a moving classification may further include anestimated rate of movement of the object identified (360).

The method may continue and store a representation of the at least onefeature in a form of metadata, including the metadata from the mastercamera associated with video of at least the slave camera in a mannerenabling retrieval of information about the object of interest (362). Acheck may be made for including slave metadata (364). If yes, slavemetadata associated with the object identified may be included (365).The method may check whether or not to store the metadata on a server(366). If yes, the metadata may be stored on the server (368).

The method may further check whether or not to present the form ofmetadata of the object to a user (370). If yes, the method may presentthe form of metadata of the object identified to a user (374). Ifpresenting, presenting the form of metadata of the object identified toa user may include presenting on any suitable display device. The methodthereafter ends (374) in this example embodiment.

FIG. 4 illustrates a flow diagram of yet another embodiment of a methodof enabling retrieval of information from a video surveillance system(400). The method may start (402) and present a representation of atleast one feature in an object of interest in a form of metadata from amaster camera and a slave camera (404) in a manner enabling retrieval ofinformation about the object of interest (406). The method thereafterends (408) in this example embodiment.

FIG. 5 is a block diagram of an example internal structure of a computer500 in which various embodiments of the present invention may beimplemented. The computer 500 contains system bus 502, where a bus is aset of hardware lines used for data transfer among the components of acomputer or processing system. Bus 502 is essentially a shared conduitthat couples different elements of a computer system (e.g., processor,disk storage, memory, input/output ports, network ports, etc.) thatenables the transfer of information between the elements. Coupled tosystem bus 502 is I/O device interface 504 for coupling various inputand output devices (e.g., keyboard, mouse, displays, printers, speakers,etc.) to the computer 500. Network interface 506 allows the computer 500to couple to various other devices attached to a network. Memory 508provides volatile storage for computer software instructions 510 anddata 512 may be used to implement embodiments of the present invention.Disk storage 514 provides non-volatile storage for computer softwareinstructions 510 and data 512 that may be used to implement embodimentsof the present invention. Central processor unit 518 is also coupled tosystem bus 502 and provides for the execution of computer instructions.

Example embodiments of the present invention may be configured using acomputer program product; for example, controls may be programmed insoftware for implementing example embodiments of the present invention.Further example embodiments of the present invention may include anon-transitory computer readable medium containing instructions that maybe loaded and executed by a processor, and, when executed, cause theprocessor to complete methods described herein. It should be understoodthat elements of the block and flow diagrams described herein may beimplemented in software, hardware, firmware, or other similarimplementation determined in the future. In addition, the elements ofthe block and flow diagrams described herein may be combined or dividedin any manner in software, hardware, or firmware. If implemented insoftware, the software may be written in any language that can supportthe example embodiments disclosed herein. The software may be stored inany form of computer readable medium, such as random access memory(RAM), read only memory (ROM), compact disk read only memory (CD-ROM),and so forth. In operation, a general purpose or application specificprocessor loads and executes software in a manner well understood in theart. It should be understood further that the block and flow diagramsmay include more or fewer elements, be arranged or oriented differently,or be represented differently. It should be understood thatimplementation may dictate the block, flow, and/or network diagrams andthe number of block and flow diagrams illustrating the execution ofembodiments of the invention.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed is:
 1. A method of enabling retrieval of informationfrom a video surveillance system, the method comprising: automaticallyidentifying an object of interest in a video scene of a master camera ora slave camera; automatically classifying at least one feature of theobject of interest to produce master and slave metadata, the object ofinterest for the slave camera being determined as a function of themaster metadata; tracking the object of interest by adjusting the slavecamera's field of view based on object information included in themaster metadata, wherein adjusting the slave camera's field of view isfurther based on processing the video scene at the slave camera based onthe master metadata; and storing the master and slave metadata inassociation with video of at least the slave camera in a manner thatenables retrieval, of information about the object of interest, throughuse of the master or slave metadata, wherein the slave metadata includesdetailed object information extracted from the video scene by the slavecamera.
 2. The method according to claim 1, wherein the storing includesstoring the master and slave metadata in a database, and further whereinthe manner that enables the retrieval of information about the object ofinterest includes: creating a link between the master and slavemetadata; and retrieving the video of the slave camera using the masteror slave metadata and the link.
 3. The method according to claim 1,wherein the manner that enables the retrieval of information about theobject of interest further includes using the master and slave metadata.4. The method according to claim 1, wherein the automaticallyidentifying includes applying background subtraction to removebackground objects from the video scene.
 5. The method according toclaim 1, wherein adjusting the slave camera's field of view includeszooming in on the object of interest and following movement of theobject of interest.
 6. The method according to claim 1, wherein theslave metadata further includes a start time stamp indicating a starttime of the slave camera's tracking the object of interest and an endtime stamp indicating an end time of the slave camera's tracking theobject of interest.
 7. The method according to claim 1, whereinprocessing the video scene includes searching of one or more imageframes of the slave camera captured during tracking, the searching beingbased on the master metadata.
 8. The method according to claim 1,wherein adjusting the slave camera's field of view includes directingthe slave camera to a pan and tilt position, the method according toclaim 5 further including: analyzing one or more image frames of theslave camera during tracking; extracting detailed object informationfrom the one or more image frames; and storing the detailed objectinformation extracted as the slave metadata.
 9. The method according toclaim 1, wherein automatically classifying the at least one feature ofthe object of interest includes categorizing the object of interest as aperson, vehicle, or animal.
 10. The method according to claim 1, whereinautomatically classifying the at least one feature of the object ofinterest includes classifying movement of the object of interest asstationary or moving, wherein a moving classification further includesan estimated rate of movement of the object of interest.
 11. The methodaccording to claim 1, wherein the master or slave metadata furtherincludes a time stamp, identified color, identified license platenumber, aspect ratio, or bounding box for the object of interest. 12.The method according to claim 1, wherein the storing includes storingthe master and slave metadata on a server.
 13. The method according toclaim 1, wherein the automatically identifying, automaticallyclassifying, and storing occur during recording of the video scene. 14.The method according to claim 1, wherein the automatically identifying,classifying, and storing occur after recording of the video scene. 15.The method according to claim 1, further including presenting the masteror slave metadata to a user.
 16. A system for enabling retrieval ofinformation from a video surveillance system, the system comprising: amaster camera, slave camera, and server communicatively coupled; themaster camera configured to identify an object of interest automaticallyin a video scene of the master camera and to communicate mastermetadata, produced by classifying at least one feature of the object ofinterest identified, to the slave camera and to the server; the slavecamera configured to determine slave metadata based on the mastermetadata communicated and to communicate the slave metadata to theserver; and the server configured to store the master and slave metadatain a manner that enables retrieval of information about the object ofinterest, wherein the master camera is further configured to include amaster bounding box for the video scene in the master metadata and theslave camera is further configured to define a slave bounding box forthe video scene based on the master bounding box, the slave metadataincluding more detailed classification information, of the object ofinterest, than the master metadata, based on slave data of the videoscene within the slave bounding box.
 17. The system of claim 16, whereinthe manner that enables retrieval of information about the object ofinterest includes creating a link between the master and slave metadataand further wherein the slave camera is further configured tocommunicate the slave metadata, the slave metadata including moredetailed classification information, of the object of interest, than themaster metadata, to the master camera or an indication that the mastermetadata communicated is incorrect.
 18. The system of claim 16, whereinthe slave camera is further configured to define the slave bounding boxas a function of the master metadata from and its own processing of thevideo scene.
 19. The system of claim 18 wherein the master metadataincludes master data of objects within the master bounding box and theslave camera is further configured to use the master data to produce theslave metadata.
 20. A method of enabling retrieval of information from avideo surveillance system, the method comprising: tracking an object ofinterest in a video scene by adjusting a slave camera's field of viewbased on object information included in master metadata, whereinadjusting the slave camera's field of view is further based onprocessing the video scene at the slave camera based on the mastermetadata; and presenting a representation of at least one feature of theobject of interest in a form of master or slave metadata from the mastercamera and the slave camera, respectively, in a manner that enablesretrieval, of information about the object of interest, through use ofthe master or slave metadata, wherein the slave metadata includesdetailed object information extracted from the video scene by the slavecamera.
 21. The method of claim 20, wherein the metadata from the mastercamera includes classification information about the object of interestand the metadata from the slave camera includes more detailedclassification information about the object of interest.